What is the difference between summer monsoons and winter monsoons?

Question

What is the difference between summer monsoons and winter monsoons?

Answer 1

its a lot warmer in the summer

Answer 2

Monsoon Systems

Monsoonal squall nears Darwin, Northern Territory

Monsoonal squall nears Darwin, Northern Territory

As monsoons have become better understood, the term monsoon has been broadened to include almost all of the phenomena associated with the annual weather cycle within the tropical and subtropical land regions of the earth.

Even more broadly, it is now understood that in the geological past, monsoon systems must have always accompanied the formation of supercontinents such as Pangaea, with their extreme continental climates.

[edit] Northeast Monsoon (Southern Asia and Australasia)

    See also: Monsoon trough

In Southern Asia, the northeastern monsoons take place from December to early March. The temperature over central Asia is less than 25°C as it is the northern hemisphere winter, therefore creating a zone of high pressure there. The jet stream in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across southern Asia, creating dry air streams which produce clear skies over India. Meanwhile, a low pressure system develops over South-East Asia and Australasia and winds are directed toward Australia known as a monsoon trough.

[edit] Northern Indian Ocean Monsoon

Onset dates and prevailing wind currents of the southwest summer monsoon.

Onset dates and prevailing wind currents of the southwest summer monsoon.

[edit] South-West Summer Monsoon

The southwestern summer monsoons occur from June through September. The Great Indian Desert (Thar Desert) and adjoining areas of the northern and central Indian subcontinent heats up too much during the hot seasons of summer. This causes a low pressure area over the northern and central Indian subcontinent. To fill up this void, the moisture-laden winds from the Indian Ocean rush in to the subcontinent. These winds, rich in moisture, are drawn towards the Himalayas, creating winds blowing storm clouds towards the subcontinent. However the Himalayas act like a high wall and do not allow the winds to pass into Central Asia, forcing them to rise. With the gain in altitude of the clouds, the temperature drops and precipitation occurs. Some areas of the subcontinent receive up to 10,000 mm of rain.

The southwest monsoon is generally expected to begin around the start of June and dies down by September. The moisture-laden winds on reaching the southernmost point of the Indian peninsula, due to its topology, become divided into two parts:

    * Arabian Sea Branch of the SW Monsoon

    * Bay of Bengal Branch of the SW Monsoon

The Arabian Sea Branch of the SW Monsoon first hits the Western Ghats of the coastal state of Kerala, India and hence Kerala is the first state in India to receive rain from the South-West Monsoon. This branch of the monsoon moves northwards along the Western Ghats giving rain to the coastal areas west of the Western Ghats. It is to be noted that the eastern parts of the Western Ghats do not receive much rain from this monsoon as the wind does not cross the Western Ghats.

View of south-west monsoon rain in Kerala.

View of south-west monsoon rain in Kerala.

The Bay of Bengal Branch of SW Monsoon flows over the Bay of Bengal heading towards North-Eastern India and Bengal, picking up more moisture from the Bay of Bengal. Its hits the Eastern Himalaya and provides a huge amount of rain to the regions of North-East India, Bangladesh and West Bengal. Mawsynram, situated on the southern slopes of the Eastern Himalaya in Shillong, India is one of the wettest places on Earth. After striking the Eastern Himalaya it turns towards the West, travels over the Indo-Gangetic Plain, at a rate of roughly 1-2 weeks per state[citation needed], pouring rain all along its way.

The monsoon accounts for 80 percent of the rainfall in the country[citation needed]. Indian agriculture (which accounts for 25 percent of the GDP and employs 70 percent of the population) is heavily dependent on the rains, especially crops like cotton, rice, oilseeds and coarse grains. A delay of a few days in the arrival of the monsoon can, and does, badly affect the economy, as evidenced in the numerous droughts in India in the 90s.

The monsoon is widely welcomed and appreciated by city-dwellers as well, for it provides relief from the climax of summer in June. However, because of the lack of adequate infrastructure in place, most major cities are often adversely affected as well. The roads, already shoddy, take a battering each year; houses and streets at the bottom of slopes and beside rivers are waterlogged, slums are flooded, and the sewers and the rare hurricane drain start to back up and pour out toxic filth rather than drain it away. This translates into various minor casualties most of the time; lack of city infrastructure coupled with changing climate patterns also causes severe damage to and loss of property and life. Bangladesh and some regions of India like in Assam and places of West Bengal experiences heavy flood, which claims huge number of lives and huge loss of property and causes severe damage to economy, as evidenced in the Mumbai floods of 2005. Also in the recent past, areas in India that used to receive scanty rainfall throughout the year, like the Thar Desert, have surprisingly ended up receiving floods due to the prolonged monsoon season.

June 1 is regarded as the date of onset of the monsoon in India, which is the average date on which the monsoon strikes Kerala over the years for which scientific data is available with the Indian Meteoreological Department.

View of central Kolkata after a monsoon rain.

View of central Kolkata after a monsoon rain.

[edit] North-East Monsoon (Retreating Monsoon)

Around September, with the sun fast retreating south, the northern land mass of the Indian subcontinent begins to cool off rapidly. With this air pressure begins to build over northern India. The Indian Ocean and its surrounding atmosphere still holds its heat. This causes the cold wind to sweep down from the Himalayas and Indo-Gangetic Plain towards the vast spans of the Indian Ocean south of the Deccan peninsular. This is known as the North-East Monsoon or Retreating Monsoon.

While traveling towards the Indian Ocean, the dry cold wind picks up some moisture from the Bay of Bengal and pours it over peninsular India. Cities like Chennai, which get less rain from the South-West Monsoon, receives rain from the Retreating Monsoon. About 50% - 60% of the rain received by the state of Tamil Nadu is from the North-East Monsoon[citation needed].

It is worth noting that North-East Monsoon (or the Retreating Monsoon) is not able to bring as much rain as the South-West Monsoon.

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